Print developer



J. TAlNl PRINT DEVELOPER Jan. 20, 1953 2 SHEETS-SHEET l Filed Aug. 5, 1949 Jan. 20, 1953 J. TAlNl 2,625,865

PRINT DEVELOPER Filed Aug. 5, 1949 2 SHEETS--SHEET 2 Z1 l 21 L 0 l o o f 1 f 22 26 27 26 52 ,2O

Patented Jan. Z0, 1953 PRINT DEVELOPER John Tain, Chicago, Ill., assignor to The C. F. Pease Company, Chicago, Ill., a, corporation of Delaware Application August 5, 1949, Serial No. 108,713

2 Claims. 1

This invention relates to improvements in gas print developers; that is, an apparatus for developing light sensitive prints by gas such as ainmonia.

A. device of this type is shown in Patent No. 2,384,155 granted September 4, 1945. In such a device a sensitized and exposed print, a diazotype print for example, is caused to pass over and across one wall of a chamber in which ammonia or other gas is being generated. The wall, hereinafter referred to as a guide wall, is constructed so as to permit the gas to pass through the wall and into contact with the print, the sensitized surface of which faces the guide wall. Heretofore, the guide wall has comprised a sheet of corrosion resistant metal, such as stainless steel, which was provided with perforations. An endless belt passes over the perforated plate and causes the print to be advanced.

This perforated plate of the prior art has certain objectionable features. For instance, the in terior of the chamber is heated to release the ammonia gas from ammonia Water with the result that the perforated plate becomes heated. When prints made of cellophane foil or of tracing cloth are passed through the machine, the heated plate causes the print to become tacky with the result that it adheres to the plate instead of sliding smoothly over it. Furthermore, the edges of the perforations cause excessive belt wear, especially along the edges of the belt which are in direct contact with the plate when narrow prints are being run through the developer.

Itis an object of my invention to provide a developer having an improved guide wall which eliminates the sticking of prints and which materially reduces belt wear, and eliminates any sliding Contact with the print.

have found that sticking may be avoided by providing a guide wall which has a lesser area of contact with the print than that area provided by a perforated plate. Furthermore, a reduction in contact area permits faster operation of the developer since a greater proportion of the sensitized surface of the print is being exposed to the action of the gas at any one instant.

A further object of my invention is to provide an improved guide wall which makes a rolling ycontact with the prints and which is constructed in such a manner that the prints cannot be inady guide wall of comparatively simple and inexpensive construction.

With reference now to the drawings in which ke reference numerals designate like parts:

Fig. 1 is a side elevation of a preferred embodiment of my invention, a portion of the casing being broken away;

Fig. 2 is a view taken generally along line 2 2 of Fig. l and showing the guide wall in front elevation;

Fig. 3 is an enlarged view of a portion of the guide wall, some of the rollers being eliminated for purposes of clarity;

Fig. 4 is a section taken along line 4 4 of Fig. 3;

Fig. 5 is a detailed perspective View showing the means for mounting the guide Wall; and

Fig. 6 is a detailed section showing the seal provided for the side edges of the belt.

Referring now to Figs. 1 and 2, the reference numeral I!! designates generally the frame of the developer, and the reference number I I, a housing which is partially broken away in Fig. l. Within the housing is disposed a gas generating chamber l2 having a guide wall I3. An endless belt I4 passes between rollers I5 and I6 and over the guide wall I3. Suitable belt tensioning rollers Ii are provided, one side of which may be adjusted by suitable means which includes a knob t8.

A guide wall I3 comprises a number of rollers i9 and 2S which are mounted 0n two series of rods '2i and 22 respectively. The rods are supported at their ends by means of end plates 23 and at intermediate portions by means of bridge plates 25 and 26. As shown in Figs. 3 and 4 the end plates and bridge plates are disposed in a plane which is generally perpendicular to the print path which is provided by the rollers I9 and 2B. The plates are maintained in spaced relationship by tie rods 21 which are secured to the end plates 23 by means of collars 28 and split washers 2Q. The ends of the tie rods may be suitably grooved for cooperation with the split washers and the collars are held in place by the usual set screws. The bridge plates are also maintained in spaced relationship by collars 28 disposed on the tie rods.

The rods of the iirst and second series 2l and 22, respectively, are supported at their ends by the end plates 23. Split washers 3l maintain the axial positions of the rods. The bridge plates i and are each provided with projecting lugs which are apertured to receive the rods 2i! or 2l whereby the rods may be supported at points intermediate the end plates. The spacing between adjoining lugs 33 on each bridge plate is equal to the spacing between alternate rods, and the 3 lugs of one plate are staggered with respect to the lugs of the other plate. Thus, the rods 2I are supported by bridge plates 25, and rods 22 are supported by bridge plates 26.

The rollers I9 and 2D, respectively, are axially spaced from each other by means of spacer 32, and at the point where the bridge plates intersect the space between adjacent rollers, half spacers 33 are employed to maintain uniform spacing of all the rollers on each rod. The spacers maintain the rollers I9 in a position opposite the space between rollers 2S and vice-versa. The spacing between adjacent rods 2| and 22 is such that the rollers I9 and 2E! overlap each other. Thus, there is no danger that a print which is being fed over the surface dened by the rollers I9 and 2D can pass through the guide wall and into the interior of the chamber I2.

The rollers are preferably crowned so as to reduce the area of contact between the print and the guide wall. Thus, a much greater proportion of the area of the print is disposed to the action of the gas than is the case when a perforated plate is used; Furthermore, since there is less area of contact, less heat will be transferred to the paper with the result that cellophane foil prints and tracing cloth prints will not soften up and stick.

The rods 2i and 22 are preferably aligned in such a manner that the surface dened by the rollers is a convex surface; thus a uniform belt pressure can be maintained. The rods 2l and 22 will not flex even under comparatively heavy belt pressures, due to the fact that they will be supported at intermediate points by bridge plates. The guide wall constitutes a structurally independent unit which may be removed for repair or replacement. The'rollers I9 and 20 are preferably screw machine products and can be made from any suitable metal which is resistant to the action of the particular gas which is employed. It has been found that the cost of a guide plate made in accordance with this invention compares favorably with the cost of a perforated plate made of heavy gauge stainless steel, which due to its thickness is very difficult to perforate.

As shown in Figs. l and 5 the guide wall I3 is removably mounted in the chamber i2 by means of an adjustable lower bracket 35 and an adjustable upper bracket 36. rChe lower bracket is engaged by the lowermost tie rod 2l, whereas the upper bracket engages the rear edges of one or more of the plates 23, 25 and 2t.

The belt rollers I and il' may be mounted to swing upwardly about the center of roller I5 to permit access to and removal of the guide wall I3.

Chamber I2 includes upper and lower marginal portions 31 which are provided with tongues 3S which project into the spaces between the first and last row of rollers I9 .as shown in Fig. 2. The chamber also includes side marginal portions 39 which are provided with corrugations de over which corrugations the edges of belt ifi slide. The corrugations provide a low friction seal between the belt and the chamber which reduces the loss of gas. As shown in Fig. l, the chamber is provided with one or more trays Gi to whichammonia water is supplied, and a heater element 152 positioned between the lowermost tray which Vserves to release the ammonia gas, as described in the aforementioned Patent No. 2,384,155.

Suitable means, not shown, may be provided to exhaust Whatever ammonia gas esca es from the chamber I2 into the housing II.

In operation, the roller I5 is driven by suitable means which causes the inner span of the belt to move upwardly across the guide wall I3. An exposed print 43 is fed between the belt I4 and the lower marginal portion 3l and is caused to advance across the guide wall where it is subjected to the developing action of ammonia or other gas. rihe print is delivered at the top of the machine and a suitable delivery tray may be provided.

Due to the provision of rollers i9 and 2B, the print will slide smoothly and without sticking, due to the fact that a rolling contact is provided and due also to the fact that the actual area of contact between the print and rollers is comparatively small. Hence, less heat will be transmitted to the surface of the print. Furthermore, the small amount of contact area exposes a greater proportion of the surface of the print to the developing action of the gas and permits faster operation.

The developer may be sold as an independent unit, or it may form a part of a combined printing and developing machine, in which case the exposed prints may be fed continuously and automatically upward into the developer.

I claim:

l. A print developer comprising means providing a chamber, one wall of which is provided with oppositely spaced side marginal portions defining an opening therebetween, a structurally inde'- pendent guide Wall disposed within said opening, a belt cooperating with said guide wall and said side marginal portions, means for driving said belt over the path provided by said guide wall, each of said side marginal portions being provided with a plurality of belt contacting portions, at least one of which is in the form of a corrugation extending in the direction of belt movement, said belt being wider than said guide Wall and engaging the belt contacting portions of each of said side marginal portions to provide a seal for preventing the escape of gas from said chamber, means for releasing a gas within said chamber for developing a print which is advanced across said guide wall by said belt, said guide wall comprising a pair of end plates, means including a tie rod for maintaining said end plates in spaced parallel relationship to provide a structurally independent unit, a first series of rods supported at their ends by said end plates, a plurality of substantially identical separate rollers coaxially mounted on each of said rods for independent rotation with respect to each other, means for axially spacing said rollers from each other, a second series of rods supported at their ends by said end plates and alternating with the rods of said rst series, a plurality of substantially identical separate rollers coaxiall-y mounted on each of the rods of said second series for independent rotation with respect to each other, and means for axially spacing said rollers from each other so that they are staggered with respect to the rollers disposed on the rods of said first series, the spacing between adjacent rods being such that said rollers are interleaved with each other to prevent a print from passing between the rollers on adjacent rods, and said rods being aligned in side by side relationship so that the rollers carried thereby define a convexly curved surface for cooperation with said belt, said rollers being crowned so as to reduce the area of Vcontact between the print and the guide wall, and a bracket mounted on said chamber providing means and engaging said tie rod for removably supporting said structurally independent guide wall in position in said opening.

2. A print developer comprising means providing a chamber, one wall of which is provided with oppositely spaced side marginal portions defining an opening therebetween, a guide wall disposed Within said opening, a belt cooperating with said guide wall and said side marginal portions, means for driving said belt over the path provided by said guide wall, each of said side marginal portions being provided with a plurality of belt contacting portions, at least one of which is in the form of a corrugation extending in the direction of belt movement, said belt being wider than said guide wall and engaging the belt contacting portions of each of said side marginal portions to provide a seal for preventing the escape of gas from said chamber, and means for releasing a gas within said chamber for developing a print which is advanced across said guide wall by said belt, said guide wall comprising a pair of end plates and two intermediately disposed bridge plates, means for maintaining said plates in spaced parallel relationship, a rst series of rods supported at their ends by said end plates, one of said bridge plates having projecting lugs for supporting the rods of said rst series at an intermediate point, a plurality of substantially identical separate crowned rollers mounted on each of said rods for independent rotation with respect to each other, means for axially spacing said rollers from each other, a second series of rods supported at their ends by said end plates and alternating with the rods of said first series, the other one of said bridge plates having projecting lugs for supporting the rods of said second series at an intermediate point, a plurality of substantially identical separate crowned rollers mounted on each of said second series for independent rotation with respect to each other, and means for axially spacing said rollers from each other so that they are staggered with respect to the rollers disposed on the rods of said rst series, the spacing between adjacent rods being such that said rollers thereon interleave with each other, and said rods being so aligned in side by side relationship that the rollers carried thereby dene a convexly curved surface for cooperation with said belt.

JOHN TAJNI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,560,579 Jones Nov. 10, 1925 1,940,202 Bodan et a1 Dec. 19, 1933 2,475,809 Sullivan et al July 12, 1949 FOREIGN PATENTS Number Country Date 846,345 France June 5, 1939 

